1. Technical Field
This invention relates generally to contact blocks for coupling electronic circuits to other devices, and more specifically to a low-profile, insert molded contact block for use in designs where space is constrained.
2. Background Art
Most all electronic products have a need to connect to other devices. For example, most all electronic devices have a need for power. Power is generally fed from a power source, like a power supply, to an electronic circuit located on a printed circuit board. The component that often facilitates this connection is a contact block.
A contact block is traditionally a piece of plastic with metal contacts wrapped around the plastic. Generally speaking, a piece of plastic is manufactured from an injection molding process. Metal contacts are then wrapped around and snapped in place. Metal leads, designed to be inserted into plated through holes on a printed wiring board, extend from the contact block and couple to the metal contacts. These metal leads are inserted into plated “through holes” in a circuit board. They are then soldered in place, often by way of a wave soldering machine. The contact block is then able to serve as an electrical connector between the electronic circuit and the outside world.
Contact blocks are heavily used in the manufacture of battery packs. All battery packs need an electrical connection to get from the rechargeable cells and internal circuitry to the outside world. This connection is necessary to be able to charge and discharge the cells. This connection is often made with a contact block.
The problem with traditional contact blocks is threefold: First, they are generally large and bulky. Traditional contact blocks typically are a centimeter or so tall, and a centimeter or two across. While one to two cubic centimeters may not sound that large, today's electronic devices, like cellular telephones, are getting smaller and smaller. Battery designers simply can not afford that much space, as some cellular telephones are now less than a centimeter thick.
Second, traditional contacts blocks, with axial leads, require solder to be applied from the bottom of the board. In an automated process, this solder is generally applied by a wave solder process. The problem is that many of today's circuit boards include only surface mounted components, all of which may be connected to the board by way of a reflow solder process. To add a through hole contact block requires either a separate wave solder machine and process, or worse, a separate hand soldering process. Both of these processes add both time and cost to the manufacture of the contact block.
Third, they are often cumbersome to construct. A piece of plastic must first be independently molded. Electrical contacts, generally requiring a U-shaped bend, must then be coupled to the plastic support member via a separate operation. These processes add both thickness and cost to the resulting contact block.
There is thus a need for an improved contact block.